An antenna module, which has a ground element disposed on a substrate and an antenna element disposed on the substrate, is disclosed in, for example, Japanese Unexamined Patent Application Publication Number 2006-345038. However, antenna modules like the above one, which are capable of providing polarization diversities, have not been known.
When two antenna modules having an identical characteristic are arranged in different directions, it may be possible to provide the antenna modules realizing a polarization diversity. In the above case, however, since each of the two antenna modules is required to have a ground element therefor, whole size of the antenna modules may increase.
For the above reason, an antenna module capable of realizing a polarization diversity with using multiple antenna elements is required. Also, it is required to downsize such an antenna module.